1. Field of the Invention
This invention relates to a device which, by allowing continuous regulation of feeler sensitivity of the piezoelectric weft passage sensor-comparator on the basis of the count of the wefts selected at any given time by the presenter, enables weaving to be effected with wefts of different count without halting the loom.
2. Discussion of Background
As is well known, in a loom the wefts originating from the bobbins are passed through the eyes of the presenter rods after traversing the channels of the piezoelectric weft passage sensor-comparator. The channels generate an electric current, the value of which is a function of the count of the wefts traversing them, this value being compared with the feeler sensitivity set by the logic unit, which halts the loom if this comparison gives a negative result. From the foregoing it follows that the use of such a weft presence sensor-comparator means that currently only wefts with the same count, and more precisely with a count corresponding to the set sensitivity, can be woven. In this respect, only one sensitivity value can be set, this value remaining constant during the entire loom operation and being changeable only by halting the loom and setting the new value, leading to a considerable reduction in loom efficiency, hence the wefts used have to be of constant count.